1. Field of the Invention
This invention relates to processes for recovering permeable gases from two gas streams containing differing percentages of the permeable gas.
2. Prior Art
It is known to separate certain gases, such as hydrogen, from gas mixtures, such as hydrogen and methane, by using membrane separation techniques. ln this operation, the gas mixture is brought into contact with a membrane permeable to the gases to be separated from the mixture, with a pressure differential being maintained across the membrane to cause the gases to permeate the membrane. High recovery rates and purities can be achieved.
It is also known to combine two gas streams to form a mixture which is then brought into contact with a membrane for separation of certain gases from the mixture by permeation techniques. This works well if both gas streams contain about the same percentage of the permeable gas. However, if the percentage of permeable gases in the two streams are significantly different, the percentage recovery or purity of the permeated gases will be low.